Conventional coaxial cables for the cable television industry, such as those shown in FIG. 6, typically include a circular center electrical conductor surrounded by a plastic or foam dielectric insulating layer of substantially constant thickness which forms an annular ring around the center electrical conductor. The outer surface of the dielectric insulating layer is covered by an outer conductor, usually an electrically conductive foil or braid or both of a material such as aluminum, and finally an outer elastomeric jacket surrounds the outer conductor.
So-called "F"-type connectors have historically been utilized to terminate the above types of coaxial cables in order to provide a continuous relationship between the center electrical conductor and the conductive foil or braid (or both) in order to effectively transmit a signal without leakage or loss of signal due to the connector and coaxial cable termination devices. F-connectors can include two, three, four, or more pieces, which are assembled together to retain a cable end. A key feature of some, is a hollow post positioned within a metal sleeve, the hollow post including a barrel portion having a raised barb. The barrel portion has a diameter which is slightly larger than the diameter of the inner dielectric insulating layer such that a prepared cable end having an exposed dielectric layer and center conductor can be positioned within the interior of the barrel. The cable is then compressed to complete the connection.
Several different methods have been employed historically to terminate the cable and complete the above assembly. Each of these methods have inherent problems. For example, one common termination method is to radially crimp the metal sleeve onto the post and barb using a hex-shaped tool. Using this method, six indents are formed, creating gaps in 60 degree intervals between the connector body and the jacket of the coaxial cable. These gaps potentially allow moisture into the connector and cause potential distortion of the coaxial cable. Moisture produces corrosion, effectively reducing signal strength and increasing resistance between the coaxial cable and the connector. In addition, because the afore mentioned leakage termination paths, RF leakage can also invariably occur between the connector and the coaxial cable's inner conductive braid shield.
Rather than using a radial crimping method for securing the coaxial cable to the connector, other F connector types use varied techniques using axial forces. For example, the EZ-F type connector manufactured by Raychem Corporation includes a compression sleeve, made from plastic or metal, in combination with the post, a retaining nut, and an outer sleeve. The compression sleeve is disposed between the post and the retaining nut and is caused to plastically deform into an open annular space defined in the post by application of an axial or longitudinal tool.
In another form of longitudinal crimp cable connector, described in U.S. Pat. No. 5,002,503, a preassembled nut, collar, and post are used in conjunction with an axially movable sleeve which fits within the open end of the collar to create a tight mechanical connection. In all known connectors which utilize longitudinal termination (e.g. use a longitudinal compression tool for termination thereof), the portion of the connector having the rotating nut is held in a stationary position and the portion of the connector body or sleeve accepting the coaxial cable moves axially in a direction toward the rotating nut of the connector. Besides the additional costs associated in the manufacture and assembly of these types of connectors, there are also leakage effects due to loosening of the connector and the cable end given that the forces are applied in the same direction as the assembly of the cable.